It is essential for a superconducting cable to circulate a refrigerant around the cable core because it is necessary to maintain the superconductor layer at a cryogenic temperature. The above-mentioned circulation of the refrigerant is essential and a structure for preventing heat invasion from outside is also essential. Further, when a superconducting cable is installed over a long distance, it is necessary to fix the position of the cable core in order to maintain the form of the cable line.
A fixation structure is proposed as the fixation structure of a conventional power cable (for example, Patent Document 1). The fixation structure includes a conductor connecting tube including insertion openings at both ends, a cylindrical electric pole, an electrical insulation unit (fixed electrical insulation portion), and a case. The connection ends of the conductor portions of two power cables connected to each other can be inserted into the insertion openings. The cylindrical electric pole maintains the conductor connecting tube with a pin capable of projecting and provided at a hole having a bottom provided at the conductor connecting tube through an elastic body. The electrical insulation unit is embedded while encompassing the electric pole. The case internally maintains the electrical insulation unit and is bonded to the ends of the two power cables.